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<TITLE>Magic-7.3 Command Reference</TITLE>
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<H2>tech</H2>
<HR>
Query properties of the current technology, or change the current
technology.
<HR>

<H3>Usage:</H3>
   <BLOCKQUOTE>
      <B>tech</B> <I>option</I> <BR><BR>
      <BLOCKQUOTE>
         where <I>option</I> may be one of the following:
	 <DL>
	   <DT> <B>load</B> <I>filename</I> [<B>-noprompt</B>][<B>-nooverride</B>]
	   <DD> Load a new technology from the file <I>filename</I>[<TT>.tech</TT>].
	   <DT> <B>help</B>
	   <DD> Display help information
	   <DT> <B>name</B>
	   <DD> Show current technology name
	   <DT> <B>filename</B>
	   <DD> Show current technology filename
	   <DT> <B>version</B>
	   <DD> Show current technology version and description strings
	   <DT> <B>lambda</B>
	   <DD> Show internal units per lambda
	   <DT> <B>planes</B>
	   <DD> Show defined planes
	   <DT> <B>layers</B> [<I>layer</I>]
	   <DD> Show defined layers
	   <DT> <B>drc</B> <I>option</I>
	   <DD> Query the DRC ruleset, where <I>option</I> is one of the
		following:
		<DL>
		  <DT> <B>width</B> <I>layer</I>
		  <DD> Return the minimum allowed width for the indicated
		       layer type.
		  <DT> <B>spacing</B> <I>layer1</I> [<I>layer2</I>]
		  <DD> Return the minimum allowed spacing between
		       <I>layer1</I> and <I>layer2</I>, if <I>layer2</I>
		       is specified, or between <I>layer1</I> and itself,
		       if not.
		</DL>
	 </DL>
      </BLOCKQUOTE>
   </BLOCKQUOTE>

<H3>Summary:</H3>
   <BLOCKQUOTE>
      The <B>tech</B> command queries aspects of the current
      technology, and can also be used to change the current
      technology.  The <B>tech load</B> command completely
      replaces the technology.  Normally a call to <B>tech load</B>
      generates a dialog window asking the user for confirmation,
      since the <B>tech load</B> command is potentially destructive
      and can cause loss of an existing layout.  The <B>-noprompt</B>
      option forces a technology load without presenting a dialog.
      This is particularly useful to put a "<B>tech load</B> <I>name</I>
      <B>-noprompt</B>" command in a <TT>.magic</TT> startup
      file in the directory of a project, so that it is not necessary to
      specify the technology on the command line when invoking <B>magic</B>.
      However, occasionally one may want to run magic from the same
      project directory with a different technology.
      The <B>-nooverride</B> option prevents the <B>tech load</B> command
      from overriding a technology name entered on the UNIX
      command line when starting <B>magic</B>. <P>

      Technology file reloading is especially useful when
      developing a technology file, to immediately see the
      results of a change made to the file.  The current
      technology can be reloaded with the simple Tcl command
      "<B>tech load [tech filename]</B>". <P>

      Note that there is a slightly different meaning between
      the command "<B>tech layers</B>" and "<B>tech layers "*"</B>".
      The former prints a formatted list of layers, including all
      aliases for each layer, to the console.  The second returns
      a Tcl list of all layers, with only the primary name for
      each layer. <P>

      A few aspects of the technology must be queried from other
      commands.  The CIF/GDS input and output styles are given
      by the <B>cif istyle</B> and <B>cif ostyle</B> commands, while
      the extraction style is given by the <B>extract style</B>
      command. <P>

      The <B>drc</B> option is intended for use by Tcl scripted
      procedures that wish to place layout while satisfying the
      DRC rules.  The two accepted <I>rule</I> options are
      <B>spacing</B> and <B>width</B>.
   </BLOCKQUOTE>

<H3>Implementation Notes:</H3>
   <BLOCKQUOTE>
      <B>tech</B> is implemented as a built-in command in <B>magic</B>.
      The command replaces the original <B>techinfo</B> command, which
      no longer exists.
   </BLOCKQUOTE>

<H3>Bugs:</H3>
   <BLOCKQUOTE>
      <B>tech drc</B> may not return the correct value in all cases.
   </BLOCKQUOTE>

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<P><I>Last updated:</I> October 16, 2004 at 1:59pm <P>
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